American Board of Opticianry (ABO) Test 2025 – 400 Free Practice Questions to Pass the Exam

For a cylinder of 1.62 diopters or greater, the tolerance for the axis is typically +/- 2 degrees. The axis refers to the orientation of the cylinder in the lens and is crucial for proper astigmatism correction. Any deviation beyond +/- 2 degrees could lead to significant visual disturbances for the patient. Therefore, maintaining precise axis alignment within this 2-degree range is essential in producing accurate and effective corrective lenses.

Options A, C, and D are incorrect as they present axis tolerance values that are not typically accepted in practice for cylinders of 1.62 diopters or greater.